Door latch assembly with vertically moved microswitch engaged by striker

ABSTRACT

An improved door latch assembly for a front-opening appliance door operated by moving a handle member in a horizontal direction, it being connected to a horizontal slide member which has an elongated opening therein encircling a roller member attached to a vertically movable bolt member movable upward upon closing of the door into engagement with a striker mechanism on the dishwasher frame, thereby securing the dishwasher door. An interlock switch is closed by pivotal movement of the striker mechanism when the latch bolt is moved into a closed position to activate the electrical system of the appliance.

United States Patent [1 1 Mercer et al.

[451 Oct. 14, 1975 DOOR LATCH ASSEMBLY WITH VERTICALLY MOVED MICROSWITCH ENGAGED BY STRIKER [75] Inventors: Robert L. Mercer; Roger M. Boor,

both of Dayton, Ohio [73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Aug. 2, 1974 [21] Appl. No.: 494,092

[52] US. Cl. ZOO/61.67; 74/110; 200/6162;

ZOO/61.64 [51] Int. Cl. H0111 27/00 [58] Field of Search ..200/61.626l.68, 153 T;

74/110; 134/57 D, 57 DL, 58 DL; 292/140, 144, 170, 201, 341.16, 341.17, 241, DIG. 69

[56] References Cited UNITED STATES PATENTS 3,005,065 10/1961 Jellies ZOO/61.62

3,246,526 4/1966 Dollheimer et a1. 74/1 10 X 3,369,807 2/1968 Whelan, Jr 74/110 X 3,841,675 10/1974 Mercer 292/241 Primary Examiner,lames R. Scott Attorney, Agent, or FirmK. l-l. MacLean, Jr.

57 ABSTRACT An improved door latch assembly for a front-opening appliance door operated by moving a handle member in a horizontal direction, it being connected to a horizontal slide member which has an elongated opening therein encircling a roller member attached to a vertically movable bolt member movable upward upon closing of the door into engagement with a striker mechanism on the dishwasher frame, thereby securing the dishwasher door. An interlock switch is closed by pivotal movement of the striker mechanism when the latch bolt is moved into a closed position to activate the electrical system of the appliance.

3 Claims, 6' Drawing Figures US, Patent Oct. 14, 1975 Sheet 1 of 3 US. Patent Oct. 14,1975 Sheet20f3 3,912,891

Patent Oct. 14,1975 Sheet30f3 3,912,891

DOOR LATCH ASSEMBLY WITH VERTICALLY MOVED MICROSWITCI-I ENGAGED BY STRIKER This invention relates to appliances of the frontloading type and, specifically, to an improved door latch assembly for such an appliance.

Appliances and particularly dishwashers presently manufactured are commonly of the front-loading variety in which the front wall of the dishwasher is openable by a door hinged along its bottom edge. The door is held in a closed position by engagement of a latch assembly with a striker mechanism. To prevent leakage in dishwashers of this type, it is essential that the door fully engage seal means around the opening.

Prior latch assemblies capable of performing the aforementioned closing function are often difficult to operate due to frictional forces resisting the closing operation of the latch. The present latch assembly produces considerable latching forces to efficiently seal the dishwasher door but at the same time generates relatively low frictional forces. Specifically, the desirable features of the latch mechanism include a manually slidable member which moves in a horizontal direction on tracks formed in the dishwasher door which has an elongated opening therein with inclined ramp-like surfaces. These surfaces are engaged by a roller member attached to a vertically movable bolt member which is mounted for sliding movement on tracks formed in the dishwasher door. When the slide member is moved horizontally to its closed position, the roller is forced to follow the ramp-like surfaces of the opening which causes the attached bolt member to move upward until it engages a striker assembly attached to the dishwasher frame.

An interlock switch in the dishwasher electrical circuit isopened by the latch assembly to prevent energization of the dishwasher when in an open mode. When the latch assembly is in a closed operative position, the switch is closed.

The angle of the ramp surfaces of the opening with respect to horizontal in the slidable member is instrumental in providing desirable high closing forces and low frictional forces. In a preferred embodiment the angle is about 10. Movement of the slide member from an open position to the closed position will multiply the force which is produced upon the roller and bolt member to produce large closing forces. In addition, the bolt member and the slide member are interconnected by the roller member which is preferably of low friction plastic material.

Therefore, an object of the present invention is to provide an efficient and smoothly operating latch assembly mechanism for doors characterized by a relatively large latching force with respect to the activating force.

A further object of the present invention is to provide an efficient and smoothly operating latch assembly for dishwasher doors or the like which includes a manually actuated slide and an adjacent bolt'movable in a direction normal to the slide with roller means engaging ramp-like surfaces to operably connect the two mem bers.

A still further object of the present invention is to provide an efficient and smoothly operating latching assembly including a horizontally slidable member which-has an elongated opening therein with inclined ramp-like surfaces with respect to horizontal and enthe resultant force transmitted to the bolt by horizontal movement of the slide being multiplied by the cotangent of the angle which the ramp-like surfaces are to horizontal.

Further objects and advantages of the present invention will be more readily apparent from the following detailed description, reference being had to the accompanying drawings in which preferred embodiments are illustrated.

In the drawings:

FIG. 1 is a front elevational view of a front-loading type dishwasher;

FIG. 2 is a fragmentary sectioned view of the dishwasher shown in FIG. 1 with the front panel broken away to reveal the latch assembly in a closed operative position;

FIG. 3 is a view similar to FIG. 2 but with the latch assembly in an open operative position;

FIG. 4 is a sectioned view of the latch assembly taken along section line 4-4 in FIG. 2 and looking in the direction of the arrows;

FIG. 5 is a sectioned view of the latch assembly taken along section 5-5 in FIG. 3 and looking in the direction of the arrows;

FIG. 6 is a sectioned view taken along section line 6-6 in FIG. 5 and looking in the direction of the arrows;

In FIG. 1 of the drawings, a dishwasher 10 is illustrated. The dishwasher is a front-loading type having a door 12 which is hinged along its bottom edge 14 so that when pivoted downward, the interior of the dishwasher is accessible to the tub for loading and unloading of dishes. An access panel 16 covers a compartment beneath the dishwasher tub in which the motor and controls are housed. Beneath the access panel 16 is a toe space 18. Mounted in a recessed channel 20 in door 12 is a handle member 22 which is adapted to be manually moved to the right and left to latch and unlatch the door 12. The handle 22 is' operably connected to a latch assembly 24 which is located behind the outer panel of the door 12 and shown in hidden lines in FIG. 1.

Details of the latch assembly 24 are shown in FIGS. 2-5 in which a front panel 26 is broken away to reveal the assembly 24. In FIGS. 2 and 4, the latch assembly 24 is shown in a closed operative mode, and in FIGS. 3 and 5, the latch assembly 24 is shown in an open operative mode. The manually slidable handle 22 is supported within the channel 20 which is formed by wall member 28. Decorative edge members 30, 32 connect the panels or walls 26, 28.

The handle 22 is operatively attached to a horizontal slide 34 by a fastener 36. The fastener is attached to a boss or extension 38 which is an integral portion of the horizontal slide member 34. The slide 34 is slidably supported by a frame member 40 for reciprocation in a horizontal direction along outward extending parallel track members 42, 44. The slide 34 is held against the track members 42, 44 by fastener means having a tumed-over head portion 46 and a washer member 48 attached to a boss 50 extending from theframe member 40.

The slide member 34 has an elongated opening 52 therethrough with circular end portions joined by ramp-like surfaces 53 inclined with respect to the horizontal. In a preferred embodiment the opening 52 has an elongated length of about 2% inches and the angle of inclination of the surfaces 53 with respect to horizontal is about The slide 34 may be a die casting or a plastic molded material. The top and bottom edges of the slide member 34 are formed to include track portions 54 and 56 adapted to engage the track members 42 and 44. Encircling the edges of the member 34 is a wall or shoulder 58 which extends therefrom to rigidify the slide.

Mounted adjacent and behind the slide 34 and extending vertically is an elongated bolt member 60. The bolt 60 is mounted for vertical reciprocation on its opposite edge portions against parallel tracks 62, 64 which extend from the plane of and are an integral part of the wall or frame 40. Bolt 60 supports a fastener member 66 which has a cylindrical surface extending into the opening to 52. Member 66 supports a plastic roller 68 which engages the surfaces 53 of slide 34. When the slide 34 is moved horizontally between operative positions shown in FIGS. 2 and 3, the fastener 66 and roller 68 are moved from one end of the elongated opening 52 to the other. Interaction between roller 68 and inclined surfaces 53 moves the bolt member 60 vertically between the closed operative position shown in FIGS. 2, 4 and the open operative position shown in FIGS, 3, 5.

In a preferred embodiment of the latch assembly, the inclination of surfaces 53 with respect to horizontal is approximately 10. The movement of the roller in the opening 52 of the preferred embodiment is approximately 2 /2 inches. Consequently, to move the roller 68 about 2 /2 inches in the elongated opening, the slide 34 is moved horizontally about 2 /32 inches, and the roller 68 is moved vertically about 15/32 of an inch. The horizontally applied force on slide 34 is multiplied when transmitted to the bolt member 60. For example, with a 10 inclined opening as illustrated in the drawings, a one-pound force upon the horizontally slidable member will produce about 5 pounds of vertical force upon the bolt member 60. This intensification of the closing force produces a smooth operating and efficient door-locking mechanism which will adequately force the dishwasher door 12 against the seal to prevent leakage.

Movement of bolt member upward from the open position shown in FIGS. 3, 5 to the closed position shown in FIGS. 2, 4 causes finger portions 70 of the bolt 60 to engage a striker mechanism 72 which is attached to the upper panel 74 of the dishwasher by a fastener 76. The upper panel 74 overlays the top wall 78 of the dishwasher tub. The striker mechanism 72 includes a member 80 which has a downwardly opening aperture 82 directly above portion 84 of the door frame 40 when the door is closed. A pin 86 supports a striker 88 which is free to pivot from an open operative position shown in FIG. 5 to a closed operative position shown in F 16.74. A rearwardly extending tab means 90 on the striker member 88 is engaged by the finger portions 70 when the bolt 60 is moved into a closed operative position. This causes the striker 88 to pivot downward through an aperture 92 in the wall portion 84. A spring 94 having one end connected to member 80 and the other end connected to striker 88 normally positions the striker in the open operative position shown in FIG. 5. The door is latched by engagement of the inclined face portions 96 of the finger portions 70 with the striker 88.

To prevent operation of the dishwasher except when bolt 60 is in the closed operative position shown in FIGS. 2 and 4, a normally open push type switch 98 with an activating portion 100 extending therefrom is supported on bolt member 60. When the striker 88 is pivoted clockwise from the position shown in FIG. 5 to the closed position shown in FIG. 4, the striker 88 engages portion 100 of switch 98 and closing an activating dishwasher circuit so the dishwasher may be operated.

Numerous modifications may be made in the invention. One change contemplated is the relocation of the switch 98 from its support on the movable member 60 to a stationary support by wall 40. In such an embodiment, the bottom 100 would be activated by movement of a pivotally mounted member contacted by striker 88.

What is claimed is as follows:

1. A latch assembly for a door having inner and outer spaced wall members comprising: an elongated slide member supported horizontally by one of said wall members; parallel track means on said door wall along which said slide member may move in a horizontal direction; a handle member attached at one end to said slide member and extending through said outer door wall member to manually impart movement to the slide member; said elongated slide member having an oblong opening therethrough characterized by parallel surfaces extending along said slide member at an angle of inclination with respect to the horizontal; a bolt member supported adjacent said slide member; parallel track means on said door wall along which said bolt member may move in a vertical direction; connecting means including a roller extending into said opening and attached to said bolt member to cause vertical movement of said bolt member when said slide member is moved in a horizontal direction; a striker assembly operably engaged by said bolt member when the latch assembly is in a closed operative mode to maintain the door in a closed position; said striker assembly including a pivotally mounted striker, one end of which is engaged by said bolt member when in a closed operative position to pivot its other end into engagement with said door wall and secure said door in a closed operative position; normally open switch means operably engaged by movement of said striker to its closed operative position thereby closing the switch means to permit the dishwasher controls to be activated.

2. A latch assembly for a door having inner and outer spaced wall members comprising: an elongated slide member supported by one of said wall members; parallel track means on said door wall along which said slide member may move in a first direction; a handle member attached at one end to said slide member and extending through said outer door wall member to manually impart sliding movement to the slide member; said slide member having an oblong opening therethrough characterized by parallel surfaces extending along the length of said slide member at at angle of inclination with respect to saidfirst direction; a bolt member supported adjacent said slide member; parallel track means on said door wall extending in a second direction substantially normal to said first direction along which said bolt member may move; connecting means including a roller extending into said opening and attached to said bolt member to cause movement of said bolt member in said second direction when said slide member is moved in said first direction; a striker assembly operably engaged by said bolt member when the latch assembly is in a closed operative mode to maintain the door in a closed position; said striker assembly including a pivotally mounted striker, one end of which is engaged by said boltmember when in a closed operative position to pivot its other end into engagement with said door wall and secure said door in a closed operative position; normally open switch means operably engaged by movement of said striker to its closed operative position thereby closing the switch means to permit the dishwasher controls to be activated.

3. A latch assembly for a door having inner and outer spaced wall members comprising: an elongated slide member supported by one of said wall members; parallel track means on said door wall along which said slide member may move in a first direction; a handle member attached at one end to said'slide member and extending through said outer door wall member to manually impart sliding movement to the slide member; said slide member having an oblong opening therethrough characterized by parallel surfaces extending along the length of said slide member at an angle of inclination with respect to said first direction; a bolt member supported adjacent said slide member; parallel track means on said door wall extending in a second direction substantially normal to said first direction along which said bolt member may move; connecting means including a roller extending into said opening and attached to said bolt member to cause movement of said bolt member in said second direction when said slide member is moved in said first direction; said angle of inclination of said parallel surfaces being about 10 whereby the actuating force on said slide member which is transmitted to said bolt member is increased; a striker assembly operably engaged by said bolt member when the latch assembly is in a closed operative mode to maintain the door in a closed position; said striker assembly including a pivotally mounted striker. one end of which is engaged by said bolt member when in a closed operative position to pivot its other end into engagement with said door wall and secure said door in a closed operative position; normally open switch means operably engaged by movement of said striker to its closed operative position thereby closing the switch means to permit the dishwasher controls to be activated. 

1. A latch assembly for a door having inner and outer spaced wall members comprising: an elongated slide member supported horizontally by one of said wall members; parallel track means on said door wall along which said slide member may move in a horizontal direction; a handle member attached at one end to said slide member and extending through said outer door wall member to manually impart movement to the slide member; said elongated slide member having an oblong opening therethrough characterized by parallel surfaces extending along said slide member at an angle of inclination with respect to the horizontal; a bolt member supported adjacent said slide member; parallel track means on said door wall along which said bolt member may move in a vertical direction; connecting means including a roller extending into said opening and attached to said bolt member to cause vertical movement of said bolt member when said slide member is moved in a horizontal direction; a striker assembly operably engaged by said bolt member when the latch assembly is in a closed operative mode to maintain the door in a closed position; said striker assembly including a pivotally mounted striker, one end of which is engaged by said bolt member when in a closed operative position to pivot its other end into engagement with said door wall and secure said door in a closed operative position; normally open switch means operably engaged by movement of said striker to its closed operative position thereby closing the switch means to permit the dishwasher controls to be activated.
 2. A latch assembly for a door having inner and outer spaced wall members comprising: an elongated slide member supported by one of said wall members; parallel track means on said door wall along which said slide member may move in a first direction; a handle member attached at one end to said slide member and extending through said outer door wall member to manually impart sliding movement to the slide member; said slide member having an oblong opening therethrough characterized by parallel surfaces extending along the length of said slide member at at angle of inclination with respect to said first direction; a bolt member supported adjacent said slide member; parallel track means on said door wall extending in a second direction substantially normal to said first direction along which said bolt member may move; connecting means including a roller extending into said opening and attached to said bolt member to cause movement of said bolt member in said second direction when said slide member is moved in said first direction; a striker assembly operably engaged by said bolt member when the latch assembly is in a closed operative mode to maintain the door in a closed position; said striker assembly including a pivotally mounted striker, one end of which is engaged by said bolt member when in a closed operative position to pivot its other end into engagement with said door wall and secure said door in a closed operative position; normally open switch means operably engaged by movement of said striker to its closed operative position thereby closing the switch means to permit the dishwasher controls to be activated.
 3. A latch assembly for a door having inner and outer spaced wall members comprising: an elongated slide member supported by one of said wall members; parallel track means on said door wall along which said slide member may move in a first direction; a handle member attached at one end to said slide member and extending through said outer door wall member to manually impart sliding movement to the slide member; said slide member having an oblong opening therethrough characterized by parallel surfaces extending along the length of said slide member at an angle of inclination with respect to said first direction; a bolt member supported adjacent said slide member; parallel track means on said door wall extending in a second dIrection substantially normal to said first direction along which said bolt member may move; connecting means including a roller extending into said opening and attached to said bolt member to cause movement of said bolt member in said second direction when said slide member is moved in said first direction; said angle of inclination of said parallel surfaces being about 10* whereby the actuating force on said slide member which is transmitted to said bolt member is increased; a striker assembly operably engaged by said bolt member when the latch assembly is in a closed operative mode to maintain the door in a closed position; said striker assembly including a pivotally mounted striker, one end of which is engaged by said bolt member when in a closed operative position to pivot its other end into engagement with said door wall and secure said door in a closed operative position; normally open switch means operably engaged by movement of said striker to its closed operative position thereby closing the switch means to permit the dishwasher controls to be activated. 